1. Field of the Invention
This invention pertains generally to a system and method for converting a stream of document pages printed in “lazy-portrait” formatting (printing across the continuous paper web to produce paired portrait orientated pages) into acceptably oriented pages that are then processed and grouped into pre-designated document sets with continuously numbered pages. More particularly to a system and method for properly orienting and page-sequencing documents that are printed on a continuous web of paper, wherein the printing format for the continuous web generates “lazy-portrait” formatted pages (printing across the paper web to produce paired portrait orientated pages) in which, when head-to-head or bottom-to-bottom paired pages are printed, one half of the printed pairs must be flipped for generation of a sequential page count in each final assembled document set.
2. Description of Related Art
To fully understand the subject invention, it is deemed worthwhile to stress the difference between existing/traditional “two-up portrait” versus the current and novel subject “lazy-portrait” printing styles and the documents produced by each type of printing scheme. Existing high-speed duplex variable data printing is carried out most frequently with continuous form printers using what is termed a “two-up portrait” format on a continuous web of paper. Two portrait printed sheets are printed side-by-side (both oriented in the same exact direction. This process, the standard in the industry, produces a continuous output of pages where, for example, the first four sheets (eight pages, front and back on four, eventually separate, sheets) appear as shown in FIG. 1. Currently, an advantage of printing in the prior art format is that it is compatible with more existing printers and more existing post-printing equipment for handling the printed sheets. A critical element of the prior art printing method is that to print either black or color markings on both pages, with the headings in color and the body in black, both the black and color-capable printing heads must span the entire width (long-side to long-side of a page) of both the duplexed sheets, WB and WC, respectively (see FIG. 1). FIG. 2 depicts a pair of traditionally formatted pages that are then separated/cut-apart and simply stacked on top of one another, as shown in FIG. 3, to produce a correctly page-sequences document set. Examples of printers that function in this manner are the IBM InfoPrint 4000 and Oce VarioStream 7000. A typical traditional printing system is seen in FIG. 4. where a continuous stream of traditionally printed sheets (such as the ones shown in FIG. 1 and/or FIG. 2) comes in from the far left and moves into a slitter that separates the single steam into two streams of continuous sheets that then enter a cutter and collator for further processing to generate correctly page-sequenced document sets (as illustrated in FIG. 3 for two cut sheets).
For the current subject invention, paper is printed in a lazy-portrait narrow-end to narrow-end (LPEE) format, which is a means for more efficient and cost effective printing of variable and form data onto paper oriented in a lazy-portrait orientation. The term “lazy-portrait” (also known in the industry as “rotated landscape” when a printer merely uses a traditional printer head alignment spanning the entire page to print a rotated image) is defined as a portrait oriented page that is generated by printing the page from one wide edge to the other wide edge (side to side) and not from narrow edge or end to narrow edge or end (top to bottom or visa-versa), as is done in every other currently existing printing system.
The critical issue with the subject invention is that when a pair of head-to-head or bottom-to-bottom pages are printed on a continuous stream of paper, the single stream of paper with the paired images must then be separated/slitted into two separate streams of paper with one stream being flipped over to correctly orient the final pages when cut and stacked into a document set. The current subject invention presents a system and method for accomplishing this sheet flipping process by flipping one entire stream of post-slitted sheets.
Again, it is noted that conventional paper transport cart systems and paper handling systems exist that can transport and process paper printed in the existing and traditional two-up portrait style (not the subject paper LPEE orientation). Future document sets have pages that are already aligned head to head, and existing finishing, cutting, and inserting equipment readily handles the orientation of the two-up portrait printed paper by slitting the two-up portrait web of paper in either first to last (1 to N) or last to first (N to 1) document page-sequencing.
Since the two-up portrait printed paper is printed narrow-end to narrow-end, there is a need to rotate/flip the stack of finished paper pages so that the document heads from both stacks (the slit stacks) of documents need to be ultimately presented and accumulated together to form a finished document set.
Various turn-bars are found on cutters for folded continuous form stacks or continuous form rolls, but the entire stream of paper is always reoriented by use of such turn-bars, completely unlike in the subject system/method in which only one half of the initial paper stream is flipped. Prior inserters handle stacks of paper that are in printed two-up portrait format with either the head of the document or the bottom of the document printed first, in either first to last sequence order, or last to first sequence order.
U.S. Pat. No. 6,994,005 (an apparatus for slitting, merging, and cutting a continuous paper web) describes an in-line turn-bar that is positioned after slitting and prior to merging the two streams, but this invention only positionally moves one slit lane of paper to overlap with another slit lane of paper, without turning over the obverse to reverse orientation (or face to back orientation). This patent differs from the subject invention in that, since there is no need, suggestion, or teaching to so, it does not turn over the paper orientation.
U.S. Pat. No. 6,595,465 (a turn-bar assembly for redirecting a continuous paper web) describes turning a single web of paper to reorient the travel direction and, in addition, to optionally flip the paper web from obverse to reverse (face up to face down) image orientation in this reoriented travel direction. This patent differs from the subject invention in that it reorients the paper direction, which is not associated with the manner in which a turn-bar is employed in the subject invention.